One metric: lines of code. The GNU Emacs I have for my Mac comes with a Lisp directory of 1.5 million non-empty lines of el code. I would think that there are

One metric: lines of code. The GNU Emacs I have for my Mac comes with a Lisp directory of 1.5 million non-empty lines of el code. I would think that there are several other Lisp applications which easily have ten times as much Lisp code.